Role of coronary artery calcium score in prediction of coronary artery stenosis in symptomatic patients with suspected coronary artery disease

Introduction The coronary artery calcium (CAC) score has been proposed as an alternative approach for stratifying cardiovascular risk. Aim To assess the role of CAC score in prediction of coronary stenosis in symptomatic patients with intermediate probability for coronary artery disease (CAD). Patients and methods A total of 80 symptomatic patients with intermediate probability for CAD underwent thorough history taking and clinical examination. Computed tomographic (CT) scan was done for all patients. A total of 48 (60%) patients with CAC score less than 400 HU (group A) underwent CT angiography: 30 (62.5%) patients had significant coronary stenosis (SCS) and were referred to invasive coronary angiography (ICA), whereas 18 (37.5%) patients had no SCS. Overall, 32 (40%) patients with CAC score more than 400 HU (group B) were referred directly for ICA. Results ICA for 62 patients was performed: 30 (62.5%) patients were referred from group A, and all had SCS (100%), whereas 30 (93.7%) patients of 32 referred from group B had SCS. Using logistic regression analysis, CAC score was the only predictor of SCS (P=0.024). Receiver operating characteristic curve data revealed CAC more than 311.2 HU as a cutoff point for prediction of SCS, with specificity of 85.0%, sensitivity of 63.3%, and area under the curve of 74.7%. CT angiography sensitivity for detection of stenosis less than or equal to 50%, stenosis more than 50%, and stenosis more than 70% was 73, 62.5, and 94%, respectively; specificity of 96.8, 99.4, and 99.4%, respectively; and overall accuracy of 85.0, 81, and 96.9%, respectively, with negative predictive value to rule out SCS 99%. Conclusion CAC score is predictive for the presence of SCS in patients, with intermediate probability for CAD.